Lead is a main-group element A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. The term is also used to refer to a pure chemical substance composed of atoms with the same number of protons. Common examples of elements are iron, copper, silver, gold, hydrogen, carbon, with symbol Pb (Latin Latin is an Italic language originally spoken in Latium and Ancient Rome. With the Roman conquest, Latin was spread to countries around the Mediterranean, including a large part of Europe. Romance languages such as Aragonese, Corsican, Catalan, French, Italian, Portuguese, Romanian, Sardinian, Spanish and others, are descended from Latin, while: plumbum) and atomic number In chemistry and physics, the atomic number is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus. It is conventionally represented by the symbol Z. The atomic number uniquely identifies a chemical element. In an atom of neutral charge, the atomic number is also equal to the number of 82. Lead is a soft, malleable Ductility is a mechanical property that describes the extent in which solid materials can be plastically deformed without fracture poor metal In chemistry, the term post-transition metal is used to describe the category of metallic elements to the right of the transition elements on the periodic table. IUPAC defines "transition elements" as either the elements in groups 3–11 or the elements in groups 3–12. According to the first definition, post-transition metals include. It is also counted as one of the heavy metals A heavy metal is a member of an ill-defined subset of elements that exhibit metallic properties, which would mainly include the transition metals, some metalloids, lanthanides, and actinides. Many different definitions have been proposed—some based on density, some on atomic number or atomic weight, and some on chemical properties or toxicity. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed to air. Lead has a shiny chrome-silver luster when it is melted into a liquid.
Lead is used in building construction, lead-acid batteries Lead-acid batteries, invented in 1859 by French physicist Gaston Planté, are the oldest type of rechargeable battery. Despite having a very low energy-to-weight ratio and a low energy-to-volume ratio, their ability to supply high surge currents means that the cells maintain a relatively large power-to-weight ratio. These features, along with, bullets A bullet is a projectile propelled by a firearm, sling, or air gun. Bullets do not normally contain explosives, but damage the intended target by impact and penetration. The word "bullet" is sometimes used to refer to ammunition generally, or to a cartridge, which is a combination of the bullet, case/shell, powder, and primer. This use and shots Lead shot is a collective term for small balls of lead. It is used primarily as projectiles in shotguns, but is also used for a variety of other purposes. It was traditionally made using a shot tower, weights, as part of solders The word solder comes from the Middle English word soudur, via Old French solduree and soulder, from the Latin solidare, meaning "to make solid", pewters Pewter is a malleable metal alloy, traditionally 85-99% tin, with the remainder consisting of copper, antimony, bismuth and lead. Copper and antimony act as hardeners while lead is common in the lower grades of pewter, which have a bluish tint. It has a low melting point, around 170–230 °C, depending on the exact mixture of metals. The word, fusible alloys An alloy is a partial or complete solid solution of one or more elements in a metallic matrix. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may be homogeneous in distribution depending on thermal history. Alloys usually have different properties from those of the and as a radiation shield Radiation protection, sometimes known as radiological protection, is the science of protecting people and the environment from the harmful effects of ionizing radiation, which includes both particle radiation and high energy electromagnetic radiation. Lead has the highest atomic number In chemistry and physics, the atomic number is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus. It is conventionally represented by the symbol Z. The atomic number uniquely identifies a chemical element. In an atom of neutral charge, the atomic number is also equal to the number of of all of the stable elements Atomic nuclei consist of protons and neutrons, which attract each other through the strong nuclear force, while protons repel each other via the electric force due to their positive charge. These two forces compete, leading to some combinations of neutrons and protons being more stable than others. Neutrons stabilize the nucleus, because they, although the next higher element, bismuth Bismuth is a chemical element that has the symbol Bi and atomic number 83. This trivalent poor metal chemically resembles arsenic and antimony. Bismuth is heavy and brittle; it has a silvery white color with a pink tinge owing to the surface oxide. Bismuth is the most naturally diamagnetic of all metals, and only mercury has a lower thermal, has a half-life Half-life is the period of time it takes for a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but may apply to any quantity which follows a set-rate decay that is so long (much longer than the age of the universe) that it can be considered stable. Its four stable isotopes have 82 protons The proton is a subatomic particle with an electric charge of +1 elementary charge. It is found in the nucleus of each atom, along with neutrons, but is also stable by itself and has a second identity as the hydrogen ion, H+. It is composed of three fundamental particles: two up quarks and one down quark, a "magic number" in the nuclear shell model of atomic nuclei The nucleus is the very dense region consisting of nucleons at the center of an atom. Almost all of the mass in an atom is made up from the protons and neutrons in the nucleus, with a very small contribution from the orbiting electrons.
Lead is a poisonous substance to animals. It damages the nervous system The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals between different parts of its body. In most animals the nervous system consists of two parts, central and peripheral. The central nervous system contains the brain, spinal cord, and retina and causes brain disorders. Excessive lead also causes blood disorders in mammals. Like the element mercury Mercury , also quicksilver (/ˈkwɪksɪlvər/) or hydrargyrum (/haɪˈdrɑrdʒɨrəm/ hye-DRAR-ji-rəm), is a chemical element with the symbol Hg (Latinized Greek: hydrargyrum, from "hydr-" meaning watery or runny and "argyros" meaning silver) and atomic number 80. A heavy, silvery d-block metal, mercury is one of six chemical, another heavy metal, lead is a potent neurotoxin A neurotoxin is a toxin that acts specifically on nerve cells , usually by interacting with membrane proteins such as ion channels. Some sources are more general, and define the effect of neurotoxins as occurring at nerve tissue. Bungarotoxin, which is considered a neurotoxin, has its effect at the motor end plate that accumulates both in soft tissues and the bones. Lead poisoning Lead poisoning is a medical condition caused by increased levels of the heavy metal lead in the body. Lead interferes with a variety of body processes and is toxic to many organs and tissues including the heart, bones, intestines, kidneys, and reproductive and nervous systems. It interferes with the development of the nervous system and is has been documented from ancient Rome Ancient Rome was a civilization that grew out of a small agricultural community founded on the Italian Peninsula as early as the 10th century BC. Located along the Mediterranean Sea, it became one of the largest empires in the ancient world, ancient Greece Ancient Greece is the civilization belonging to the period of Greek history lasting from the Archaic period of the 8th to 6th centuries BC to 146 BC and the Roman conquest of Greece after the Battle of Corinth. At the center of this time period is Classical Greece, which flourished during the 5th to 4th centuries BC, at first under Athenian, and ancient China Chinese civilization originated in various regional centers along both the Yellow River and the Yangtze River valleys in the Neolithic era, but the Yellow River is said to be the Cradle of Chinese Civilization. The written history of China can be found as early as the Shang Dynasty . Oracle bones with ancient Chinese writing from the Shang Dynasty.
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Characteristics
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Lead is bright and silvery when freshly cut but the surface rapidly tarnishes in air to produce the commonly observed dull luster normally associated with lead. It is a dense The density of a material is defined as its mass per unit volume. The symbol of density is ρ . In some countries (for instance, in the United States), density is also defined as its weight per unit volume . The density of a substance is the reciprocal of its specific volume, a representation commonly used in thermodynamics, ductile Ductility is a mechanical property that describes the extent in which solid materials can be plastically deformed without fracture, very soft, highly malleable, bluish-white metal that has poor electrical conductivity Electrical conductivity or specific conductance is a measure of a material's ability to conduct an electric current. When an electrical potential difference is placed across a conductor, its movable charges flow, giving rise to an electric current. The conductivity σ is defined as the ratio of the current density J to the electric field strength when compared to most other metals. This metal is highly resistant to corrosion Corrosion is the disintegration of an engineered material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as oxygen. Formation of an oxide of iron due to oxidation of the iron atoms in solid solution is a, and because of this property, it is used to contain corrosive liquids (for example, sulfuric acid Sulfuric acid is a strong mineral acid with the molecular formula H2SO4(aq). It is soluble in water at all concentrations. Sulfuric acid has many applications, and is one of the top products of the chemical industry. World production in 2001 was 165 million tonnes, with an approximate value of US$8 billion. Principal uses include lead-acid). Because lead is very malleable and resistant to corrosion it is extensively used in building construction – for example in the external coverings of roofing joints.
Metallic lead can be toughened by addition of small amounts of antimony Antimony ;[note 2] Latin: stibium) is a chemical element with the symbol Sb and an atomic number of 51. It has two stable isotopes, one with seventy neutrons, the other with seventy-two. A silvery lustrous grey metalloid, it is found mainly as antimony sulfide, commonly known as stibnite, or of a small number of other metals such as calcium Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth most abundant element by mass in the Earth's crust. Calcium is also the fifth most abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride,. All isotopes Isotopes are different types of atoms of the same chemical element, each having a different number of neutrons. In a corresponding manner, isotopes differ in mass number (or number of nucleons) but never in atomic number. The number of protons (the atomic number) is the same because that is what characterizes a chemical element. For example, of lead, except for lead-204, can be found in the end products of the radioactive decay Radioactive decay is the process by which an unstable atomic nucleus spontaneously loses energy by emitting ionizing particles and radiation. This decay, or loss of energy, results in an atom of one type, called the parent nuclide transforming to an atom of a different type, named the daughter nuclide. For example: a carbon-14 atom emits radiation of the even heavier elements, uranium Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, in which 6 of the electrons are valence electrons. The uranium nucleus binds between 141 and 146 neutrons, establishing six isotopes, the most and thorium Thorium is a chemical element with the symbol Th and atomic number 90.
Creation
Lead-204 is believed to have been created in supernovae by the r-process The r-process is a nucleosynthesis process, likely occurring in core-collapse supernovae responsible for the creation of approximately half of the neutron-rich atomic nuclei that are heavier than iron. The process entails a succession of rapid neutron captures on seed nuclei, typically Ni-56, hence the name r-process. The other predominant of nucleosynthesis Nucleosynthesis is the process of creating new atomic nuclei from pre-existing nucleons . It is thought that the primordial nucleons themselves were formed from the quark-gluon plasma from the Big Bang as it cooled below two trillion degrees. A few minutes afterward, starting with only protons and neutrons, nuclei up to lithium and beryllium (both. Lead-206 was also created in stars by the s-process The S-process or slow-neutron-capture-process is a nucleosynthesis process that occurs at relatively low neutron density and intermediate temperature conditions in stars. Under these conditions the rate of neutron capture by atomic nuclei is slow relative to the rate of radioactive beta-minus decay. A stable isotope captures another neutron; but a of nucleosynthesis.
Isotopes
Main article: Isotopes of lead Lead has four stable isotopes - 204Pb, 206Pb, 207Pb, 208Pb and one common unstable radiogenic isotope 202Pb with a half-life of ~53,000 years. The standard atomic mass (abundance-weighted average of the stable isotopes) is 207.2(1) u. It is the element with the heaviest stable isotope. (The more massive 209Bi, long considered to be stable,Lead can be found or produced in many isotopes Isotopes are different types of atoms of the same chemical element, each having a different number of neutrons. In a corresponding manner, isotopes differ in mass number (or number of nucleons) but never in atomic number. The number of protons (the atomic number) is the same because that is what characterizes a chemical element. For example,, with four of them being stable. The four stable isotopes of lead are 204Pb, 206Pb, 207Pb, and 208Pb with 204Pb regarded as completely primordial lead, and 206, 207, 208 being formed probably from the radioactive decay Radioactive decay is the process by which an unstable atomic nucleus spontaneously loses energy by emitting ionizing particles and radiation. This decay, or loss of energy, results in an atom of one type, called the parent nuclide transforming to an atom of a different type, named the daughter nuclide. For example: a carbon-14 atom emits radiation of two isotopes of uranium (U-235 and U-238) and one isotope of thorium Thorium is a chemical element with the symbol Th and atomic number 90 (Th 232).
The one common radiogenic isotope 1) In comparison with the quantity of the radioactive 'parent isotope' in a system, the quantity of the radiogenic 'daughter product' is used as a radiometric dating tool of lead, 202Pb, has a half life Half-life is the period of time it takes for a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but may apply to any quantity which follows a set-rate decay of about 53,000 years.[1]
Chemistry
Various oxidized forms of lead are easily reduced to the metal. An example is heating PbO with mild organic reducing agents such as glucose. A mixture of the oxide and the sulfide heated together will also form the metal.[2]
- 2 PbO + PbS → 3 Pb + SO2
Metallic lead is attacked (oxidized) only superficially by air, forming a thin layer of lead oxide that protects it from further oxidation. The metal is not attacked by sulfuric Sulfuric acid is a strong mineral acid with the molecular formula H2SO4(aq). It is soluble in water at all concentrations. Sulfuric acid has many applications, and is one of the top products of the chemical industry. World production in 2001 was 165 million tonnes, with an approximate value of US$8 billion. Principal uses include lead-acid or hydrochloric Hydrochloric acid is the solution of hydrogen chloride (H acids. It does, however, dissolve in nitric acid Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming nitric acid. Fuming nitric acid is characterized as white fuming nitric acid and red fuming nitric acid, depending on the amount of nitrogen dioxide present with the evolution of nitric oxide Nitric oxide or nitrogen monoxide (systematic name) is a chemical compound with chemical formula N gas to form dissolved Pb(NO3)2.
- 3 Pb + 8 H+ + 8 NO−3 → 3 Pb2+ + 6 NO−3 + 2 NO + 4 H2O
When heated with nitrates of alkali metals, metallic lead oxidizes to form PbO (also known as litharge), leaving the corresponding alkali nitrite. PbO is representative of lead's +2 oxidation state. It is soluble in nitric and acetic acids, from which solutions it is possible to precipitate halide, sulfate, chromate, carbonate (PbCO3), and basic carbonate (Pb3(OH)2(CO3)2) salts of lead. The sulfide can also be precipitated from acetate solutions. These salts are all poorly soluble in water. Among the halides, the iodide is less soluble than the bromide, which, in turn, is less soluble than the chloride.[3]
Lead(II) oxide is also soluble in alkali hydroxide solutions to form the corresponding plumbite salt.[2]
- PbO + 2 OH− + H2O → Pb(OH)2−4
Chlorination of plumbite solutions causes the formation of lead's +4 oxidation state.
- Pb(OH)2−4 + Cl2 → PbO2 + 2 Cl− + 2 H2O
Lead dioxide is representative of the +4 oxidation state, and is a powerful oxidizing agent. The chloride of this oxidation state is formed only with difficulty and decomposes readily into lead(II) chloride and chlorine gas. The bromide and iodide of lead(IV) are not known to exist.[3] Lead dioxide dissolves in alkali hydroxide solutions to form the corresponding plumbates.[2]
- PbO2 + 2 OH− + 2 H2O → Pb(OH)2−6
Lead also has an oxide with mixed +2 and +4 oxidation states, red lead (Pb3O4), also known as minium.
Lead readily forms an equimolar alloy with sodium metal that reacts with alkyl halides to form organometallic compounds of lead such as tetraethyl lead.[4]
Chloride complexes
Diagram showing the forms of lead in chloride media.[5]Lead(II) forms a series of complexes with chloride, the formation of which alters the corrosion chemistry of the lead. This will tend to limit the solubility of lead in saline media.
| Pb2+ + Cl− → PbCl+ | K1 = 12.59 |
| PbCl+ + Cl− → PbCl2 | K2 = 14.45 |
| PbCl2 + Cl− → PbCl3− | K3 = 3.98 ×10−1 |
| PbCl3− + Cl− → PbCl42− | K4 = 8.92 × 10−2 |
Phase diagrams of solubilities
See also: Phase diagramLead(II) sulfate is poorly soluble, as can be seen in the following diagram showing addition of SO42− to a solution containing 0.1 M of Pb2+. The pH of the solution is 4.5, as above that, Pb2+ concentration can never reach 0.1 M due to the formation of Pb(OH)2. Observe that Pb2+ solubility drops 10,000 fold as SO42− reaches 0.1 M.
| Plot showing aqueous concentration of dissolved Pb2+ as a function of SO42− [5] | Diagram for lead in sulfate media[5] |
Here it can be seen that the addition of chloride can lower the solubility of lead, however in chloride rich media (such as aqua regia) the lead can become soluble again as anionic chlorocomplexes.
| Diagram showing the solubility of lead in chloride media. The lead concentrations are plotted as a function of the total chloride present.[5] | Pourbaix diagram for lead in chloride (0.1 M) media[5] |
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Sun, 05 Sep 2010 13:10:43 GMT+00:00
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The FLHC
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Q. I have been playing electric for about 9 years and want to get you opinion on a good, impressive instrumental lead guitar song for a school competition. Looking for something a little different from canon rock and satriani, but any suggestions welcome :)
Asked by Alex - Sun Nov 15 09:59:53 2009 - - 6 Answers - 0 Comments
A. Summer Presto by Antonio Vivaldi. It's traditionally played on violins, but here's a link to a performance using guitars (and yes, it's summer presto, not "presto from summer" or whatever they titled it as): I would advise against attempting it unless you're already rather proficient with fast lead, but it's absolutely beautiful.
Answered by Lexi - Mon Nov 16 15:59:23 2009
